Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Available For Sale Securities [Abstract]
Total Available-For-Sale, Amortized Cost	$ 6,815	$ 6,824
Total available-for-sale, fair value	6,793	6,692
Held To Maturity Securities [Abstract]
Total Held-To-Maturity, Amortized Cost	2,793	2,801
Total held-to- maturity, fair value	2,695	2,651
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Due in one year or less	664
Due after one year through five years	1,259
Due after five years through ten years	919
Due after ten years	1,684
Mortgage-Backed and Asset-Backed	1,667
Total Available-For-Sale, Amortized Cost	6,193	5,897
Due in one year or less	665
Due after one year through five years	1,280
Due after five years through ten years	923
Due after ten years	1,697
Mortgage-Backed and Asset-Backed	1,605
Total available-for-sale, fair value	6,170	5,764
Fixed Maturities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Held To Maturity Securities [Abstract]
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,793
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, Amortized Cost	2,793
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,695
Mortgage-Backed and Asset-Backed	0
Total held-to- maturity, fair value	$ 2,695